BAGHDAD, Iraq (CNN) -- An audio message attributed to Izzat Ibrahim al-Douri, the highest ranking former member of Saddam Hussein's regime still at large, salutes the "People of Palestine" and calls on them to fight back against Israel in Gaza.

A 1999 file image of Izzat Ibrahim al-Douri, who served under Saddam Hussien's regime and who is still at large.

"We say to the people of Gaza, give more resistance and we will be with you in the field, and know that our victory in kicking out the invaders is your victory as well, because the main assailant on the nation and on Palestine is the American imperialism," the recording said.

"A salute to the martyrs of the massacre, and our condolences to their families."

Al-Douri's recording follows reports of a similarly defiant message from al Qaeda's deputy chief a day earlier. Ayman al-Zawahiri reportedly vowed revenge for Israel's air and ground assault on Gaza and called Israel's actions against Hamas militants "a gift" from U.S. President-elect Barack Obama.

Israel is in the 12th day of a military operation against Hamas militants, who have been firing rockets from Gaza into southern Israel.

Al-Douri's 30-minute recorded message was broadcast Wednesday on al-Raei Iraqi satellite television over an old picture of al-Douri, wearing his Iraqi military uniform.

CNN has not been able to independently verify the authenticity of the voice on the tape.

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This is not al-Douri's first purported audio message. There have been at least four others over the past three years in addition to a statement attributed to him.

Al-Douri, 66, served as vice-chairman of Hussein's Revolutionary Command Council. He remains at large nearly six years after the war in Iraq began.

He has previously been reported killed and captured, although those reports later turned out to be erroneous.

He was the King of Clubs (No. 6) on the U.S. military's card deck of most wanted regime officials.

The U.S. military says he has helped finance the insurgency against U.S. troops in Iraq with Iraqi funds he transferred to Syria before Hussein's government collapsed in April 2002. But it says his influence has waned while he has been in hiding.

U.S. officials say al-Douri played key roles in the chemical attack on the Kurdish town of Halabja in 1988 and in putting down Kurdish and Shiite revolts after the 1991 Persian Gulf War.